With all eyes on transfers, the biggest news at Arsenal this January was arguably the release of the club’s 2017-18 financial results. No one has a crystal ball when it comes to sports outcomes, but knowing the finances of a European football club allows you to predict their competitive fortunes with a fair bit of accuracy. In Arsenal’s case, while the headlines will crow about a record breaking profit, the 2017-18 financial results are actually a portent of potentially challenging times ahead. Now more than ever, Arsenal’s need to return to the Champions League has come into sharp focus.

Arsenal reported a pre-tax profit of £70 million—a £25 million increase from the prior year. That profit not only represents a record number for the club, but also the highest any Premier League club reported for 2017-18, and the third highest in league history. As a result of the increased profits, Arsenal’s cash account surged from an impressive £180.1 million to an...